This invention deals with display systems for visually reproducing characters such as Arabic decimal numerals, alphameric characters and various symbols, and the specific construction of the displays and the display units used in the systems.
There are known systems using various types of display units such as (1) electric lamp actuated systems represented by U.S. Pat. No. 3,622,224--J. J. Wysocki et al.--Nov. 23, 1971, (2) light emitting diode systems as shown in U.S. Pat. No. 3,840,873--S. Usui--Oct. 8, 1974, (3) liquid crystal display systems as shown in U.S. Pat. No. 3,613,351--R. S. Walton--filed May 13, 1969 or U.S. Pat. No. 3,975,085--T. Yamada et al.--Aug. 17, 1976, and (4) plasma type display systems as shown in U.S. Pat. Nos. 3,989,981--J. Ogle et al.--Nov. 2, 1976; 3,989,974--H. Tottori et al.--Nov. 2, 1976; and 3,890,609--R. Sasaki et al.--June 17, 1975.
Particularly in battery operated systems and other systems requiring low energy consumption, the liquid crystal display elements are advantageous. These crystal displays are highly developed with various driving systems and crystal element panel wiring layouts. Thus, a rectangular wiring matrix of crossed conductors on opposite sides of the crystal is shown in U.S. Pat. No. 3,410,999--J. L. Fergason et al.--Nov. 12, 1968 and in U.S. Pat. No. 3,982,239--S. Sherr--Sept. 21, 1976. Other crystal element wiring patterns and shapes are known such as when a color picture of a bottle is presented in U.S. Pat. No. 3,576,364--L. A. Zanoal--Apr. 27, 1971, and with a common solid conductor on one side of the crystal as in U.S. Pat. No. 3,600,060--D. C. Kettering et al.--Aug 17, 1971. Special character display patterns are also known such as a "FIG. 8 matrix" in U.S. Pat. No. 4,142,182--A. R. Kmetz--Feb. 27, 1979 or an array of slot-like elements in an array with some isolated and some interconnected as shown in U.S. Pat. No. 4,121,202--W. J. M. Gissane--Oct. 17, 1978.
Also the transparancy characteristics of liquid crystal displays permitting see through is recognized in U.S. Pat. No. 3,703,329--J. A. Castellano--Nov. 21, 1972 and U.S. Pat. No. 3,903,519--B. Zega--Sept. 2, 1975 for example.
The need to simplify electronic switching and selection systems by special patterns of discrete and separate display element areas is recognized by J. M. Lapeyre in U.S. Pat. Nos. 4,112,424--Sept. 5, 1978 and 3,872,463--Mar. 18, 1975, where respectively fourteen and sixteen element areas have subsets selectable to display Arabic decimal numerals 0-9. Also advantages of a slanted off-vertical array of element positions in producing visibly legible characters are set forth. However, there remains some fundamental problems with display systems that are not solved by the prior art. Thus, for example, switching and control systems have remained complex in most instances, particularly where battery life is saved by time shared pulsing of display devices at a rate not discernable by the human eye and therefore giving the appearance of continuous energization.
When the display panel is liquid crystal, then the contrast is limited and when elements become small they are difficult to distinguish. The display is further complicated by difficult manufacturing techniques, handling a myriad of wires, many being so thin that reliability is a problem, and being limited to patterns not permitting common overlap areas on both sides of the crystal, which might display non selected patterns or "noise". Also definition of characters in an esthetically pleasing pattern easily seen is a problem particularly with liquid crystal displays.
In displays including cathode glow plasma type displays, there are strict limitations placed upon wiring layouts and positions of elements to prevent overlap of wires on opposite sides of the active materials causing unwanted visual changes. Sometimes areas outside desired character element areas are masked by painting, etc.
It is therefore a general object of this invention to provide improved display systems which resolve these prior art deficiencies.
One special object of the invention is to provide display systems with advantageous electrode patterns.
More specifically, it is an object of the invention to produce display systems with simplified energization circuitry legible and pleasing visual display of selected characters, and compatible with energy saving techniques and liquid crystal display elements.
Other features, objectives and advantages will be found throughout the following description, drawings and claims.